Die-hard zombie fans (are there any other kind?) are probably already very familiar with Mr Steven Yeun, aka Glenn, one of a group of survivors navigating a post-apocalyptic zombie wasteland in the FX drama The Walking Dead. What they might not know, however, is that prior to his success with the show (the all-time highest-rated cable drama in the US) the South Korean-born, Michigan-raised Mr Yeun cut his teeth at Chicago's contrastingly more lighthearted The Second City theatre - the legendary improv comedy company responsible for introducing the world to the likes of Messrs Alan Arkin, Bill Murray, Steven Colbert and Ms Tina Fey to name a few.

"I was there with Vanessa Bayer, who is part of Saturday Night Live's current cast," he says. "I remember we used to always try to pitch a sketch about a racist cab driver, but it never worked out."

Speaking from California the day after the premiere of the third series of The Walking Dead in LA, Mr Yeun talks about his days in Chicago, his secret obsession with men's fashion, and, of course, the living dead.

Considering Glenn is rarely seen out of the same outfit, how do you approach dressing yourself?

I like solids and looking clean, but it's more an architectural thing. I'm kind of just a nut about design. In high school my planner was always filled in and perfectly straight. I guess you could call me OCD.

Are you the same with your hair?

Yes, but because of the show I'm not allowed to cut it. It's the bane of my existence, but it's probably better that way, because otherwise I'd be crazy about it.

Do you have a uniform?

Yes, a grey T-shirt and jeans, with wingtips. I've got to say, I love J.Crew's T-shirts. Right now I'm wearing one of those with a fat, cable-knit cardigan.

What can we expect from Glenn this season?

Without giving away any spoilers, I think it's safe to say this season you'll see a side of him you've never seen before. What's great about Glenn is that it's a growth part as well as a story of a man finding things to live for when the apocalypse comes.

How did you get involved with improv and Second City?

I was introduced to it when I joined the improv troupe at the small little arts college I went to. When I got out I was contemplating medical school, but so many of my heroes had been involved with Second City I decided I'd just move to Chicago for two years and see where it took me. I moved out to LA a few years later, in 2009, to act full time, which you can't really do in Chicago.

the work

the premiere

Mr Yeun attending The Walking Dead season two TV series premiere, LA, October 2011

the zombie killer

Mr Yeun appearing in the promo for the third season of The Walking Dead, September 2012

Other than what I'm doing now with The Walking Dead, it was the greatest experience of my life. Nothing beats live theatre and comedy. The immediate feedback is one of the most amazing feelings ever. The best thing about it was we weren't getting paid that much - only $90 a show - and because it's Chicago there is no business outside of improv like film or TV, so everyone was there because they loved it.

When did you know the show was a hit?

At first I couldn't really fathom what was going on, and in a way I still can't. We're isolated in Atlanta, so you don't really get an outside perspective. Yesterday I was sitting in my hotel room before the premiere and all of a sudden it hit me that, holy crap, so many people actually watch this.

Do you still do comedy?

I still do improv whenever I can. Mainly at a show called Wet Hands at ImprovOlympic, and whenever my friends from Second City in LA get together. It's hard though, because shooting The Walking Dead means I'm away in Atlanta for a big chunk of the year. I shoot as much comedy as I can, and I write as well. Right now I'm writing a guest column for [Dave Eggers' satirical literary journal] The Believer, and I'm also working on a screenplay, which feels like it will never get done.

Why does comedy have so much appeal?

It's my roots. I see comedy as more of a challenge. You can stick drama in comedy, but putting comedy in drama isn't so effective. Actually, if we find we have a laugh in The Walking Dead, the tone doesn't fit and you have to kill it.